Ui_text without background

Dashboard
2

add a ui_template set to HEAD with a <style> tag

use CSS and appropritate selector to set it transparent e,g,

<style>
[node-id="d773305b.7df838"] {
    background-color: transparent !important;
}
</style>

where d773305b.7df838 is the id of the ui_text as can be seen in the node
image